As telecommunications technology has evolved, more advanced network access equipment has been introduced that can provide services that were not possible previously. This network access equipment might include systems and devices that are improvements of the equivalent equipment in a traditional wireless telecommunications system. Such advanced network access equipment may be included in evolving wireless communications standards, such as long-term evolution (LTE). For example, in an LTE system the advanced network access equipment might include an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) node B (eNB). In various wireless communications systems, the advanced network access equipment may include a base station a wireless access point, or a similar component operable as an access node according to a corresponding wireless communications standard. Any such component will be referred to herein as an eNB, but it should be understood that such a component is not necessarily an eNB. Such a component may also be referred to herein as an access node or base station.
LTE may be said to correspond to Third Generation Partnership Project (3GPP) Release 8 (Rel-8 or R8), Release 9 (Rel-9 or R9), and Release 10 (Rel-10 or R10), and possibly also to releases beyond Release 10, while LTE Advanced (LTE-A) may be said to correspond to Release 10 and possibly also to releases beyond Release 10. While the present disclosure is described in relation to an LTE-A system, the concepts are equally applicable to other wireless communications systems as well.
As used herein, the term “user equipment” (alternatively “UE”) refers to equipment that communicates with an access node to obtain services via the wireless communications system. A UE might in some cases refer to mobile devices such as mobile telephones, personal digital assistants, handheld or laptop computers, and similar devices that have telecommunications capabilities. Such a UE might include a device and its associated removable memory module, such as but not limited to a Universal Integrated Circuit Card (UICC) that includes a Subscriber Identity Module (SIM) application, a Universal Subscriber Identity Module (USIM) application, or a Removable User Identity Module (R-UIM) application. Alternatively, such a UE might include the device itself without such a module. In other cases, the term “UE” might refer to devices that have similar capabilities but that are not transportable, such as desktop computers, set-top boxes, or network appliances. The term “UE” can also refer to any hardware or software component that can terminate a communication session for a user. Also, the terms “user equipment,” “UE,” “user agent,” “UA,” “user device,” and “mobile device” might be used synonymously herein.